thanks...we have to be careful that the locals can easily negotiate the roadways up to each plot (nice catch ...they are not used to hills)....but once on their own plot, they buy into spectacular views/ elevated living.

Originally posted by abrowne

.. then 20% is reasonable over a lot, so long as there remains a buildable envelope. No-disturb covenants and other hillside regulations should also apply.....

In most codes I've administered, 10% street slope and 12% lot slope is generally the maximum. This is based on local soil characteristics and a regional effort to preserve slopes as a desired natural feature.

Around here pretty much anywhere i've ever done work in has the same requirements for overland slope:

Min = 1.5%
Max = 3:1 (33%)

When doing a grading plan, if it is a lot with a steep drop-off, and I used 3:1 slopes to catch grade, I do like to provide some usable yard area. Generally around 10' front and sides, 20' rear. you don't want to go 3:1 right from the house.

ok...for areas where there is no traffic or vehicle access, I'm working on 20 percent slope front to back on a 30m (98') deep house lot.
The plot gets sold as is- and engineered by the purchaser with restrictions on allowable cut and fill with minimum percentages of slope left in a 'natural' state. It is a man made hill after all

At between 15% - 20%, the difference in elevation between the front and rear of the home is about 1 storey, which allows for walk-out basements to happen. This is also, coincidentally, a nice slope that can be achieved without significant earthworks or retaining walls. Getting beyond this though, you start dealing with having to push dirt about more significantly, which leads to visual scarring and all that other lovely stuff.

Other things to consider hillside wise is the depth of front setback (keep it minimal), how parking is handled (make it from edge-of-pavement, not edge of lot line) and allowable continuous vertical surfaces (think about big, blank walls shooting up several stories from the downslope perspective) versus terraced effects for retaining walls and buildings.

At between 15% - 20%, the difference in elevation between the front and rear of the home is about 1 storey, which allows for walk-out basements to happen. This is also, coincidentally, a nice slope that can be achieved without significant earthworks or retaining walls. Getting beyond this though, you start dealing with having to push dirt about more significantly, which leads to visual scarring and all that other lovely stuff.

Other things to consider hillside wise is the depth of front setback (keep it minimal), how parking is handled (make it from edge-of-pavement, not edge of lot line) and allowable continuous vertical surfaces (think about big, blank walls shooting up several stories from the downslope perspective) versus terraced effects for retaining walls and buildings.